Systems and methods for performing peritoneal dialysis

ABSTRACT

In a peritoneal dialysis embodiment of the present invention, spent dialysate from the patient&#39;s peritoneal cavity passes, along a patient loop, through a dialyzer having a membrane that separates waste components from the spent dialysate, wherein the patient loop returns fresh dialysate to the patient&#39;s peritoneal cavity. The waste components are carried away in a second regeneration loop to a regeneration unit or sorbent cartridge, which absorbs the waste components. The regeneration unit removes undesirable components in the dialysate that were removed from the patient loop by the dialyzer, for example, excess water (ultrafiltrate or UF), toxins and metabolic wastes. Desirable components can be added to the dialysate by the system, such as glucose and electrolytes. The additives assist in maintaining the proper osmotic gradients in the patient to perform dialysis and provide the necessary compounds to the patient.

PRIORITY CLAIM

[0001] This application claims the benefit of U.S. Provisional PatentApplication No. 60/397,131, filed Jul. 19, 2002, entitled “Systems AndMethods For Performing Peritoneal Dialysis”, the entire contents ofwhich are hereby incorporated by reference and relied upon.

BACKGROUND OF THE INVENTION

[0002] The present invention generally relates to dialysis systems. Morespecifically, the present invention relates to regeneration dialysissystems and continuous flow dialysis systems. The present invention alsorelates to methods of performing dialysis therapies.

[0003] Due to disease, insult or other causes, a person's renal systemcan fail. In renal failure of any cause, there are several physiologicalderangements. The balance of water, minerals and the excretion of dailymetabolic load is no longer possible in renal failure. During renalfailure, toxic end products of nitrogen metabolism (urea, creatinine,uric acid, and others) can accumulate in blood and tissues.

[0004] Kidney failure and reduced kidney function have been treated withdialysis. Dialysis removes waste, toxins and excess water from the bodythat would otherwise have been removed by normal functioning kidneys.Dialysis treatment for replacement of kidney functions is critical tomany people because the treatment is life saving. One who has failedkidneys could not continue to live without replacing at least thefiltration functions of the kidneys.

[0005] Hemodialysis and peritoneal dialysis are two types of dialysistherapies commonly used to treat loss of kidney function. Hemodialysistreatment utilizes the patient's blood to remove waste, toxins andexcess water from the patient. The patient is connected to ahemodialysis machine and the patient's blood is pumped through themachine. Catheters are inserted into the patient's veins and arteries toconnect the blood flow to and from the hemodialysis machine. As bloodpasses through a dialyzer in the hemodialysis machine, the dialyzerremoves the waste, toxins and excess water from the patient's blood andreturns the blood to infuse back into the patient. A large amount ofdialysate, for example about 120 liters, is used to dialyze the bloodduring a single hemodialysis therapy. The spent dialysate is thendiscarded. Hemodialysis treatment lasts several hours and is generallyperformed in a treatment center about three or four times per week.

[0006] One type of hemodialysis therapy is regenerative hemodialysis.This therapy uses a hemodialysis system, which includes a cartridge fordialysate regeneration. One such cartridge is manufactured under thename REDY™ by Sorb Technology, Oklahoma City, Okla. In this system, thedialysate fluid flow path must be properly cleaned before thehemodialysis machine can be used on another patient. Also, the dialysatefluid flow path is not a closed system, i.e., the dialysate fluid flowpath is open to the atmosphere, such that oxygen from the atmosphere cancontact fluid in the system and foster the growth of bacteria in same.Consequently, contamination of such a dialysis system can be a concern.Further, the dialysate fluid exiting the REDY™ cartridge is not suitablefor peritoneal dialysis because the fluid is relatively acidic and not,therefore, physiologic. Moreover, this system requires the attention ofmedical personnel during therapy.

[0007] Peritoneal dialysis utilizes a sterile, pyrogen free dialysissolution or “dialysate”, which is infused into a patient's peritonealcavity. The dialysate contacts the patient's peritoneal membrane in theperitoneal cavity. Waste, toxins and excess water pass from thepatient's bloodstream through the peritoneal membrane and into thedialysate. The transfer of waste, toxins, and water from the bloodstreaminto the dialysate occurs due to diffusion and osmosis, i.e., an osmoticgradient occurs across the membrane. The spent dialysate drains from thepatient's peritoneal cavity and removes the waste, toxins and excesswater from the patient. This cycle is repeated on a semi-continuous orcontinuous basis.

[0008] There are various types of peritoneal dialysis therapies,including continuous ambulatory peritoneal dialysis (“CAPD”) andautomated peritoneal dialysis. CAPD is a manual dialysis treatment, inwhich the patient connects an implanted catheter to a drain and allows aspent dialysate fluid to drain from the peritoneal cavity. The patientthen connects the catheter to a bag of fresh dialysate and manuallyinfuses fresh dialysate through the catheter and into the patient'speritoneal cavity. The patient disconnects the catheter from the freshdialysate bag and allows the dialysate to dwell within the cavity totransfer waste, toxins and excess water from the patient's bloodstreamto the dialysate solution. After a dwell period, the patient repeats themanual dialysis procedure.

[0009] In CAPD the patient performs several drain, fill, and dwellcycles during the day, for example, about four times per day. Eachexchange or treatment cycle, which includes a drain, fill and dwell,takes about four hours. Manual peritoneal dialysis performed by thepatient requires a significant amount of time and effort from thepatient. This inconvenient procedure leaves ample room for improvementand therapy enhancements to improve patient quality of life.

[0010] Automated peritoneal dialysis is similar to continuous peritonealdialysis in that the dialysis treatment includes a drain, fill, anddwell cycle. However, a dialysis machine automatically performs three tofour cycles of peritoneal dialysis treatment, typically overnight whilethe patient sleeps.

[0011] With automated peritoneal dialysis, an automated dialysis machinefluidly connects to an implanted catheter. The automated dialysismachine also fluidly connects to a source or bag of fresh dialysate andto a fluid drain. The dialysis machine pumps spent dialysate from theperitoneal cavity, though the catheter, to the drain. The dialysismachine then pumps fresh dialysate from the dialysate source, throughthe catheter, and into the patient's peritoneal cavity. The automatedmachine allows the dialysate to dwell within the cavity so that thetransfer of waste, toxins and excess water from the patient'sbloodstream to the dialysate solution can take place. A computercontrols the automated dialysis machine so that the dialysis treatmentoccurs automatically when the patient is connected to the dialysismachine, for example, when the patient sleeps. That is, the dialysissystem automatically and sequentially pumps fluid into the peritonealcavity, allows for dwell, pumps fluid out of the peritoneal cavity, andrepeats the procedure.

[0012] Several drain, fill, and dwell cycles will occur during thetreatment. Also, a “last fill” is often used at the end of the automateddialysis treatment, which remains in the peritoneal cavity of thepatient when the patient disconnects from the dialysis machine for theday. Automated peritoneal dialysis frees the patient from having tomanually performing the drain, dwell, and fill steps. Automated dialysiscan improve the patient's dialysis treatment and undoubtedly improvesthe patient's quality of life.

[0013] So-called “continuous flow” peritoneal dialysis (“CFPD”) systemsthat purport to provide continuous dialysate flow exist. However, thesesystems typically have a single pass fluid flow. That is, the dialysateflows into, through, and out of the peritoneal cavity one time beforebeing sent to a drain. The “spent” dialysate (waste laden dialysate)from the patient collects in a drain bag, which is discarded, or runsinto a household drain or other drain. Known CFPD systems, therefore,typically use a volume of disalysate one time and then discard it. Thatis, the systems have no ability to regenerate or reuse a quantity ofdialysate.

[0014] The effectiveness of existing peritoneal dialysis therapies, andexisting systems which perform the therapies, depends upon the amount ofdialysis fluid used. For example, typical peritoneal dialysis therapyrequires about 4 to 6 exchanges of dialysate (drain, fill, dwell) withabout 2 to 3 liters of dialysate for each exchange. Peritoneal dialysisis a daily therapy performed 7 days per week. As a consequence, 240 to540 liters of fresh dialysate must be delivered to and stored at apatient's home each month. Increasing dialysate dosage to increasetherapy effectiveness will necessitate even more dialysate.

[0015] Therefore, needs exist to provide improved dialysis systems andmethods of performing dialysis. Particularly, needs exist to provideclosed loop peritoneal dialysis systems and methods that regenerate orreuse spent dialysate. There are needs for such systems and methods tobe compatible with CFPD treatment so that patients can perform theprocedure at home without the need for storing an inordinate amount offresh dialysate bags. There are further needs for such systems andmethods to be automated so that the procedure can be largely performedat night while the patient sleeps.

SUMMARY OF THE INVENTION

[0016] Generally, the present invention provides improved dialysissystems and improved methods of performing dialysis. More particularly,the present invention provides systems and methods for continuous flowdialysis (“CFD”) and regenerative dialysis, and in combination,continuous flow regenerative dialysis (“CFRD”). This invention alsoincludes improved systems and methods for performing hemodialysis.

[0017] The dialysis system of the present invention automaticallyperforms dialysis therapy on a patient, for example, during nighttimewhile the patient sleeps. The present invention automaticallyregenerates spent dialysate into fresh dialysate that is reintroducedinto the patient to be used again for dialysis treatment. Further, thedialysis system provides continuous fluid flow simultaneously to andfrom the patient.

[0018] To this end, in one embodiment of the present invention a systemfor providing dialysis is provided. The system includes a patient fluidloop having a first pump and multiple patient lumens. The systemincludes a second fluid loop including a second pump and a medical fluidregenerator. A membrane device is placed in fluid contact with andseparates the patient and the second fluid loops. The membrane deviceallows at least one selected component of the fluid in the patient fluidloop to transfer to the second fluid loop. The second loop is otherwiseclosed except for the transfer of the selected component via themembrane device. A controller is also provided that operates the firstand second pumps to recirculate fluid in the patient loop and the secondloop.

[0019] The system is adaptable to be used with various different typesof components and to be arranged in a variety of ways.

[0020] For example, in an embodiment, the membrane device is a dialyzer.

[0021] In an embodiment, a pressure gradient exists across the membranedevice.

[0022] In an embodiment, the patient loop is also closed except for thetransfer of the selected component via the membrane device and theventing of air/gas.

[0023] In an embodiment, the membrane device includes a nanofilter whichallows urea to pass from the patient fluid loop to the second fluidloop.

[0024] In an embodiment, the medical fluid regenerator includes a uremictoxin sorbent.

[0025] In an embodiment, the medical fluid regenerator can include anyor all of the following materials: urease, zirconium phosphate,zirconium oxide, and carbon.

[0026] In an embodiment, the system includes a gas separator thatremoves gas from one or both of the patient and second fluid loops.

[0027] In an embodiment, the gas separator and the medical fluidregenerator are provided in a single device.

[0028] In an embodiment, the system includes a gas vent that vents gasesfrom the patient and second fluid loops.

[0029] In an embodiment, the second fluid loop includes a multi-analytesensor that monitors a concentration of electrolytes in the medicalfluid.

[0030] In an embodiment, peritoneal dialysis fluid is circulated throughthe patient fluid loop.

[0031] In an embodiment, blood is circulated through the patient fluidloop.

[0032] In an embodiment, at least parts of the patient fluid loop andthe second fluid loop are provided in a disposable device.

[0033] In an embodiment, the second fluid loop includes a balancechamber that balances flow within the second fluid loop.

[0034] In an embodiment, the controller enables fluid to flow inopposite directions through the multiple patient.

[0035] In an embodiment, the system includes a dual lumen catheter thatdefines the multiple patient lumens.

[0036] In an embodiment, one or both of the patient fluid loop and thesecond fluid loop includes an in-line fluid heater.

[0037] In an embodiment, the in-line fluid heater includes a radiantheater and a plate heater.

[0038] In an embodiment, the system includes a medical fluid sensorwhich senses one or more indicators including: ammonia, ammonium and pH.

[0039] In an embodiment, the system includes a fluid volume sensor in orboth of the patient and second fluid loops.

[0040] In an embodiment, the fluid volume sensor includes a capacitancefluid volume sensor that uses a chamber in fluid communication with oneor both of the fluid loops.

[0041] In an embodiment, the chamber is a pump chamber.

[0042] In an embodiment, the system includes an ultrafiltrate containerin fluid communication with at least one of the patient and second fluidloops.

[0043] In an embodiment, the system includes a fluid concentratecontainer in fluid communication with one or both of the patient andsecond fluid loops.

[0044] The system as described herein uses, in one embodiment, adisposable dialysis cassette. The cassette includes a flexible membranecovering a patient pump chamber and a regeneration pump chamber. Thecassette includes an apparatus for fluidly connecting the patient pumpchamber to a closed loop patient fluid path. The cassette furtherincludes an apparatus for fluidly connecting the regeneration pumpchamber to a closed loop regeneration fluid path. The patient path andthe regeneration path each fluidly communicates with a dialyzer.

[0045] The cassette is adaptable to be used with various different typesof components and to be arranged in a variety of ways.

[0046] For example, in an embodiment, the disposable cassette defines afluid path leading to a port that fluidly communicates with a dialysatesorbent cartridge.

[0047] In an embodiment, the disposable cassette defines a fluid pathleading to a port that fluidly communicates with a gas separator.

[0048] In an embodiment, the disposable cassette defines a fluid pathleading to a port that fluidly communicates with a dialysis concentratecontainer.

[0049] In an embodiment, the disposable cassette defines a fluid pathleading to a port that fluidly communicates with a dialysate last bag.

[0050] In an embodiment, the disposable cassette defines a fluid pathleading to a port that fluidly communicates with a dialysate bag.

[0051] In an embodiment, the disposable cassette defines a fluid pathleading to a port that fluidly communicates with a drain container.

[0052] In an embodiment, the disposable cassette defines a fluid pathleading to a port that fluidly communicates with a patient fluidconnector.

[0053] Further, the disposable cassette can define a fluid path for atwenty-four hour collection and/or a remote analyte sensor.

[0054] The disposable cassette operates with a dialysis therapy device.The therapy device includes a housing having a portion that receives thedisposable cassette. The housing houses a patient pump actuator thatpumps fluid through a patient path defined at least in part by thedisposable cassette. The housing also houses a regeneration pumpactuator that pumps fluid through a regeneration path defined at leastin part by the disposable cassette.

[0055] The dialysis therapy device is also adaptable to be used withvarious different types of components and to be arranged in a variety ofways.

[0056] For example, in an embodiment, the dialysis therapy deviceincludes at least one fluid volume measurement sensor component thatcooperates with the patient pump actuator and the regeneration pumpactuator.

[0057] In an embodiment, the housing houses a fluid heater.

[0058] In an embodiment, the housing houses at least one sensor, such asan ammonia sensor, an ammonium sensor and a pH sensor.

[0059] In an embodiment, the housing houses at least one valve actuatorthat operates with the disposable cassette.

[0060] The present invention includes a plurality of different methodsfor operating the systems and apparatuses described herein. In oneembodiment, a method is provided for moving fluid in a dialysis system.The method includes continuously recirculating a first fluid through apatient loop. The method includes continuously recirculating a secondfluid through a regeneration loop. At least one waste component issimultaneously transferred from the patient loop to the regenerationloop through a device shared by both loops. The loops are otherwiseclosed except for the fluid transfer through the device. The method alsoincludes removing the at least one waste component from the regenerationloop.

[0061] The first and second fluids can both include dialysate.Alternatively, the first fluid includes blood and the second fluidincludes dialysate.

[0062] In an embodiment, the method includes flowing the second fluid inthe regeneration loop through a waste sorbent and absorbing at leastsome of the waste component.

[0063] In an embodiment, the method includes the step of heating the atleast one of the first and second fluids.

[0064] In an embodiment, the method includes the step of removingultrafiltrate from at least one of the first and second fluids.

[0065] In an embodiment, the method includes the step of addingdialysate to at least one of the first and second fluids.

[0066] In an embodiment, the method includes the step of addingconcentrate to at least one of the first and second fluids.

[0067] In an embodiment, the method includes the step of removing gasfrom at least one of the first and second fluids.

[0068] In an embodiment, the method includes the step of balancing theflow of fluid in at least one of the patient loop and the regenerationloop.

[0069] In an embodiment, the method includes the step of sensing avolume of flow of fluid in at least one of the patient loop and theregeneration loop.

[0070] In an embodiment of any of the methods described herein,recirculating dialysate fluid through the patient loop includes passingthe fluid through a portion of a patient.

[0071] In an embodiment, the method is for continuous flow peritonealdialysis and includes passing the dialysate fluid and the regenerationfluid past opposite sides of a dialyzer membrane and regenerating theregeneration fluid after the regeneration fluid exits the dialyzer.

[0072] In an embodiment of the continuous flow peritoneal dialysismethod, recirculating dialysate fluid through the closed patient loopincludes passing the fluid through a sleeping patient.

[0073] In an embodiment of the continuous flow peritoneal dialysismethod, recirculating dialysate fluid through the closed patient loopincludes passing the fluid through a patient at nighttime.

[0074] In another embodiment, a method of moving fluid in a peritonealdialysis system is provided. The peritoneal dialysis method includes thesteps of: (i) continuously recirculating dialysate through a containerin a patient loop; (ii) continuously recirculating dialysate through thecontainer in a regeneration loop; and (iii) continuously moving at leastone waste component from the patient loop to the regeneration loopthrough the container shared by both loops, the loops being closedexcept for said transfer through said container.

[0075] In an embodiment, the peritoneal dialysis method includes thestep of recirculating dialysate through the regeneration loop at adifferent rate than a rate at which dialysate is recirculated throughthe patient loop.

[0076] In a further method of the present invention, performingcontinuous flow dialysis includes multiple dialysis disciplines. Themethod includes performing continuous flow peritoneal dialysis with aclosed loop dialysis device at a first point in time and performingcontinuous flow hemodialysis via the same closed loop dialysis device ata second point in time.

[0077] In an embodiment, the continuous flow peritoneal dialysis and thecontinuous flow hemodialysis are performed on the same patient.

[0078] In an embodiment, the method includes an intermediate step ofremoving a disposable cassette used with the device and coupling a newdisposable cassette to the device.

[0079] In an embodiment, the method includes an intermediate step ofremoving a dual lumen peritoneal dialysis catheter and replacing thecatheter with a hemodialysis needle.

[0080] In an embodiment, the method includes an intermediate step ofremoving a hemodialysis needle and replacing the needle with a duallumen peritoneal dialysis catheter.

[0081] One advantage of the present invention is to provide improvedsystems and methods for performing dialysis.

[0082] Another advantage of the present invention is to provide improvedsystems and methods for performing automated continuous flow dialysissystems and methods.

[0083] A further advantage of the present invention is to provideregenerative dialysis systems and methods of operating same.

[0084] Still another advantage of the present invention is to provide aregenerative dialysis system that has clinical advantages.

[0085] Still a further advantage of the present invention is to providea regenerative dialysis system that has economic advantages.

[0086] Yet another advantage of the present invention is to provide aregenerative dialysis system that has quality of life advantages.

[0087] Still further, an advantage of the present invention is toprovide a regenerative dialysis system that reduces the amount ofdialysis fluid need to perform dialysis.

[0088] Another advantage of the present invention is to provide a closedloop dialysis system.

[0089] Other advantages of the present invention are to provide systemsand methods for performing both peritoneal dialysis and hemodialysis.

[0090] Additional features and advantages of the present invention aredescribed in, and will be apparent from, the following DetailedDescription of the Invention and the figures.

BRIEF DESCRIPTION OF THE FIGURES

[0091]FIG. 1 schematically illustrates an embodiment of a dialysissystem according to the principles of the present invention.

[0092]FIG. 2 shows a multi-lumen patient fluid connector according tothe principles of the present invention.

[0093]FIG. 3 schematically illustrates another embodiment of a dialysissystem according to the principles of the present invention.

[0094]FIG. 4 schematically illustrates a further embodiment of adialysis system according to the principles of the present invention.

[0095]FIG. 5 illustrates an embodiment of a disposable cassetteaccording to the present invention.

[0096]FIG. 6 illustrates another embodiment of a disposable cassetteaccording to the present invention.

[0097]FIG. 7 illustrates a disposable cassette of the present inventionconnected to various fluid containers.

[0098]FIG. 8 schematically illustrates yet another embodiment of adialysis system according to the principles of the present invention.

[0099]FIG. 9 schematically illustrates an embodiment of a dialysissystem according to the principles of the present invention thatprovides hemodialysis.

[0100]FIG. 10 illustrates a combination container providing variouscomponents used in the dialysis systems of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0101] Generally, the present invention relates to dialysis systems andmethods of performing dialysis. In an embodiment, the present inventionpertains to continuous flow regeneration peritoneal dialysis systems andmethods. In other embodiments the present invention pertains tonon-continuous flow regeneration peritoneal dialysis, and regenerationhemodialysis, both continuous and non-continuous flow.

[0102] The dialysis system automatically performs dialysis therapy on apatient, for example during nighttime while the patient sleeps. Thepresent invention can provide true continuous flow dialysis therapy(fluid simultaneously flowing into and out of the patient), andautomatically regenerate spent dialysate into fresh dialysate that isagain used for the dialysis treatment. Continuous flow of dialysatetends to increase the efficacy of treatment by maximizing or maintaininga maximum osmotic gradient across the peritoneal membrane. Regenerationof dialysate by the present invention significantly reduces the amountof dialysate required for a treatment. For example, the amount ofdialysate fluid can be reduced from about fifty liters for CFPD therapyif performed by an existing cycler to about six to eight liters of samefor therapy with the present invention.

[0103] In a peritoneal dialysis embodiment of the present invention, thespent dialysate from the patient's peritoneal cavity passes through aregeneration unit and is regenerated into a useable dialysate. Theregenerated dialysate in a patient fluid loop is returned to thepatient's peritoneal cavity to further dialyze the patient. Theregeneration unit removes undesirable components in the dialysate thatwere removed from the patient, for example, excess water (ultrafiltrateor UF), toxins, and metabolic wastes, so that the dialysate can be usedfor further dialysis. Desirable components can be added to the dialysateby the system, such as glucose and electrolytes, for example. Theadditives assist in maintaining the proper osmotic gradients in thepatient to perform dialysis and provide the necessary compounds to thepatient.

[0104] Continuous flow peritoneal dialysis according to the presentinvention means that when the patient is being dialyzed (e.g., dialysateis being pumped to and removed from the peritoneal cavity), thedialysate is constantly and simultaneously flowing into and out of thepatient. The dialysis system pumps fresh dialysate into the patient'speritoneal cavity while simultaneously pumping spent dialysate out ofthe peritoneal cavity. Accordingly, the dialysis system can eliminatethe dwell period inside the peritoneal cavity that is typical forexisting dialysis systems. The flow rate of the continuous dialysateflow can be constant or varied as desired, and is generally about100-300 ml/min.

[0105] The dialysis system of the present invention can be controlled toprovide various dialysis therapies, as desired. Accordingly, even thoughthe dialysis system can provide continuous flow, the present inventionalso supports non-continuous flow or batch systems and methods. Also,the continuous flow into and out of the peritoneal cavity occurs duringthe main therapy treatment, so that a dwell during a last bag, forexample, does not detract from the continuous flow feature. Furthermore,the fluid pumping mechanisms of the present invention may provide forbrief intermittent fluid flow, such as the filling of a pump chamber,for example. The continuous fluid flow of the present invention isconsidered to include such brief intermittent fluid flow.

[0106] The dialysis systems and methods of the present invention provideadvantages compared to other dialysis systems and therapies, such asclinical advantages, economic advantages, and quality of lifeadvantages, for example. It is believed that the present invention hasclinical advantages, such as, improved blood pressure (“BP”) control,improved hematocrit (“HCT”) control, improved fluid volume control,improved preservation of residual renal function (“RRF”), improvedadequacy vs. the National Kidney Foundation's DOQI standard, higherefficiency (clearances/time), lower glucose absorption, glucoseprofiling and ultrafiltrate management, and reduced catheter channeling.

[0107] It is also believed that the present invention has economicadvantages, such as, reduced therapy cost and reduced Epogen (“EPO”)usage. Further, it is believed that present invention has quality oflife advantages, such as, increased awake time free from dialysisdevices, improved patient access, reduced complexity, reducedself-administration of drugs, reduced therapy training, elimination ofthe need for having a home water infrastructure, a reduced amount offluid that the patient must handle and manage, simpler prescriptions andelimination of patient transportation to dialysis centers.

[0108] The dialysis systems and methods of the present invention moreclosely simulate and replace continuous kidney functioning as comparedto intermittent dialysis therapies. This, in turn, can contribute toimproved clinical outcomes (RRF, HCT, BP, for example) while minimallyimpacting the patient's lifestyle. The efficiency and convenience of thepresent invention provides patients with a renal replacement therapythat is relatively unrestrictive. This allows patients to have greaterfreedom from limitations experienced by dialysis devices and therapies.The present invention can provide easier entrance into early dialysistherapy because the system can enable the physician to retain apatient's RRF while minimally impacting the patient's lifestyle.

Dual Loop System

[0109] Referring now to the drawings and in particular to FIG. 1, asystem 10 for providing dialysis treatment to a patient needing same isillustrated. As illustrated in FIG. 1, two loops are provided: a patientloop (a recirculating patient fluid flow path) 12 and a regenerationloop 14 (a recirculating dialysate fluid flow path). However, it shouldbe noted that the present invention can be used in a system includingonly one loop or more than two loops. The patient loop 12 is used todialyze the patient 16 with dialysate in a peritoneal dialysisembodiment. The regeneration loop 14 also contains dialysate and is usedto regenerate the dialysate in the patient loop 12. In a hemodialysisembodiment, the patient loop 12 carries the patient's blood, and theregeneration loop 14 dialyzes the blood and regenerates the dialysate inthe loop 14.

[0110] As illustrated generally in FIG. 1, the patient loop 12 and theregeneration loop 14 are initially filled or primed with dialysate fluidfrom a bag 18 by pumping the dialysate through a pump, such as anultrafiltrate pump 19. FIG. 1 shows a single dialysate bag 18 for boththe patient and regeneration loops 12 and 14; however, separatedialysate bags and/or fluid pumps could be individually used for thepatient loop 12 and the regeneration loop 14. In a hemodialysisembodiment, the patient loop 12 can be primed with a suitable primingsolution, such as a saline solution, and then connected to the patient'sblood circulatory system.

[0111] The patient loop 12 is fluidly connected to the patient 16 by amulti-lumen patient fluid connector 20 and catheter. Referring to FIGS.1 and 2, the multi-lumen patient fluid connector 20 can have, forexample, a single housing 70 having more than one separate lumen 72 (topatient lumen) and 74 (from patient lumen), or separate housings eachhaving one of the lumens 72 and 74. In a peritoneal dialysis embodiment,the multi-lumen patient fluid connector 20 can be connected to a duallumen catheter 22 (illustrated in FIG. 1), such as a catheter disclosedin co-pending U.S. patent application Ser. No. 09/689,508, titled“Peritoneal Dialysis Catheters,” incorporated by reference or othermulti-fluid path patient access.

[0112] The dual lumen catheter 22 is implanted in the patient 16 andprovides fluid flow access to the patient's peritoneal cavity. Twoseparate lumens 72 and 74 of the multi-lumen patient connector 20 arefluidly connected to separate lumens (not illustrated) of the dual lumencatheter 22. Fluid in the patient loop 12 can continuously flow throughthe patient fluid connector 20 simultaneously and continuously inmultiple directions, e.g. two different directions, into and out of thecatheter 22 and the patient 16. The multi-lumen patient fluid connector20 is described in further detail below in FIG. 2.

[0113] In a continuous flow embodiment, the patient loop 12 can befluidly connected to the patient by any device or devices that providesfor fluid to simultaneously flow into and out of the patient. Forexample, the patient loop 12 can be connected to the dual lumen catheterto two single lumen catheters.

[0114] In FIG. 1, the patient loop 12 has a patient fluid pump 24 thatpumps fluid through the patient loop 12. The fluid in the patient loop12 is pumped from the patient 16 (the patient's peritoneal cavity in aperitoneal dialysis embodiment) through the patient fluid connector 20,through a dialyzer 26, back through the patient fluid connector 20, andis returned to the patient 16. In a peritoneal dialysis embodiment, thespent dialysate (laden with waste and excess water) in the patient loop12 exiting from the patient 16 is cleansed or regenerated by passingthrough the dialyzer 26. The waste, such as urea, creatinine and excesswater passes from the patient loop 12 across a dialyzer membrane 28 tothe regeneration loop 14 to produce fresh dialysate exiting the dialyzerin the patient loop 12. The fresh dialysate is returned to the patient16 for further dialysis treatment. In an embodiment, the fluid in thepatient loop 12 is continuously recirculated through the patient loop 12by the patient pump 24. Also, the dialyzer 26 provides a sterileindependent barrier between the patient loop 12 and the regenerationloop 14. Existing dialyzers used for dialysis is therapy are suitablefor use with the present invention, for example. Also, the membrane 28referred to in the dialyzer 26 includes any suitable filter material,such as hollow dialyzer fibers.

[0115] In a hemodialysis embodiment, the patient loop 12 is connected tothe patient's blood circuit rather than the peritoneal cavity. Thepatient pump 24 continuously recirculates the blood, as the dialyzer 26removes waste and excess from the blood.

[0116] The regeneration loop 14 removes the waste and excess water fromthe patient loop 12. In the embodiment illustrated in FIG. 1, a fluidpump 30, pumps dialysate fluid in the regeneration loop 14 continuouslyto recirculate the dialysate through the loop 14. The dialysate fluidpump 30 pumps the dialysate from the dialyzer 26, through a sorbentcartridge 32, and back to the dialyzer 26. The fluid in the regenerationloop 14 flows past a side of the dialyzer membrane 28 opposite the sideof the membrane 28 having the fluid in the patient loop 12. In anembodiment, the regeneration loop 14 provides for balanced fluid flowthrough the dialyzer 26, for example, by providing equal flow dialysatefluid pumps 30, and/or balance chambers.

[0117] As mentioned above, waste and excess water passes from the fluidin the patient loop 12, across the dialyzer membrane 28, to the fluid inthe regeneration loop 14. The transfer across the dialyzer membrane 28occurs at least in part due to diffusion and concentration gradientsacross the membrane 28. Also, the system 10 in an embodiment maintains alower fluid pressure in the regeneration loop 14 relative to the patientloop 12. That is, there is a transmembrane pressure (“TMP”) across thedialyzer membrane 28. The fluid pressure differential draws fluid fromthe patient loop 12, across the dialyzer membrane 28, to theregeneration loop 14. This fluid pressure differential can be maintainedby removing fluid from the regeneration loop 14, for instance, by usingthe ultrafiltrate pump 19 to drain some of the fluid in the regenerationloop 14. The amount or rate of fluid removed from the regeneration loop14 by the ultrafiltrate pump 19 determines the amount or rate of fluidtransferring from the patient loop 12, across the dialyzer membrane 28,to the regeneration loop 14. This amount or rate equals the amount orrate of fluid removed from the patient 16 to the patient loop 12.

[0118] A sorbent cartridge or container 32 includes materials thatabsorb particular compounds from the dialysate. For example, certainsorbents within the sorbent cartridge 32 may absorb uremic toxins, suchas urea, creatinine, uric acid, and other metabolism by-products. Byremoving these undesirable waste materials, the sorbent cartridge 32 atleast partially regenerates the dialysate. The sorbent cartridge 32includes a body having a fluid inlet 34 and a fluid outlet 36. Onesorbent cartridge 32 according to the invention contains four layers ofmaterials, including a first layer of urease, a second layer ofzirconium phosphate, a third layer of zirconium oxide and a fourth layerof carbon. The interior of the cartridge 32 is constructed and arrangedso that the fluid entering the interior from the inlet 34 flows(preferably upward and uniformly) through the first layer, the secondlayer, the third layer, the fourth layer and finally through the outlet36.

[0119] The sorbent cartridge 32 can also use materials that selectivelyremove certain solutes from the dialysate. The selective materials caninclude a binder or reactive sorbent material capable of selectivelyremoving urea, a binder or reactive sorbent material capable ofselectively removing phosphate and/or the like. The use of materialscapable of selective removal of solutes, particularly urea, enhances thecleaning efficiency of the system of the present invention such that theamount of dialysate necessary for effective treatment can be minimized.

[0120] The materials that can selectively remove solutes from solution,such as binder materials, can include a variety of suitable anddifferent materials including, for example, polymeric materials that arecapable of removing nitrogen-containing compounds, such as urea,creatinine, other like metabolic waste and/or the like in solution. Ingeneral, these types of materials contain a functional group(s) thatchemically binds with urea or other like solutes.

[0121] For example, U.S. Pat. Nos. 3,933,753 and 4,012,317, eachincorporated herein by reference, disclose alkenylaromatic polymerscontaining phenylglyoxal that can function to chemically bind urea. Ingeneral, the phenylglyoxal polymeric material is made via acetylationperformed in, for example, nitrobenzene followed by halogenation of theacetyl group and treatment with dimethylsulfoxide as disclosed in U.S.Pat. Nos. 3,933,753 and 4,012,317. Another example of a polymericmaterial that is capable of selectively removing solutes, such as urea,from solution includes polymeric materials that contain a tricarbonylfunctionality commonly known as ninhydrin as disclosed in U.S. Pat. No.4,897,200, incorporated herein by reference. However, it should beappreciated that the present invention can include any suitable type ofmaterial or combinations thereof to selectively remove solutes, such asurea, from solution as previously discussed.

[0122] In addition to absorbing certain materials from the dialysate,the sorbent cartridge 32 may also modify the dialysate in theregeneration loop 14 in other ways. For example, the materials in thesorbent cartridge 32 mentioned above or additional materials added tothe cartridge 32 may modify the pH of the fluid passing through thecartridge 32. In an embodiment, the pH of the dialysate in theregeneration loop 14 is modified as needed to maintain a physiologiclevel. One sorbent cartridge 32 is described in further detail in a U.S.patent application titled “Method and Composition for Removing UremicToxins in Dialysis Processes,” Ser. No. 09/990,673, incorporated hereinby reference.

[0123] The sorbent cartridge 32 can also include a number of componentsin addition to the sorbent materials capable of removing solutes fromthe dialysate. For example, the cleaning cartridge may have thecapability to remove all or a portion of electrolytes, such as sodium,potassium, or the like, from the dialysate solution. In this case, anadditional source of electrolytes in solution may be needed to replenishthe dialysate after it has been cleaned. The cartridge may also beconfigured to release bicarbonate or the like into the system dependingon the type of sorbent material used. This can facilitate pH regulationof the dialysate. As necessary, the cartridge may be filtered to preventproteins, particulate matter or like constituents from leaching orexiting from the cartridge and into the dialysate.

[0124] Ultrafiltrate (excess water) removed from the patient 16 can beremoved from the dialysis system 10 by draining the ultrafiltrate to adrain bag 38 or other drain means. In one embodiment, the ultrafiltratepump 19 removes fluid from the regeneration loop 14 at the exit end ofthe dialyzer 26 through valves 40 and 42 to the drain bag 38, whereinthe fluid contains the waste and excess water removed from the patientloop 12 by the dialyzer 26. The drain pump 19 can remove fluid from theregeneration loop 14 continuously or intermittently (e.g., batchoperation), as desired.

[0125] The dialysis solution in the regeneration loop 14 is removed fromthe system along with the ultrafiltrate. Accordingly, a dialysateconcentrate is provided in a concentrate container 44 to supplynecessary compounds to the regeneration loop 14. The concentrate fromthe container 44 mixes with the dialysate in the regeneration loop 14and adds the compounds to the dialysate. The concentrate in anembodiment also includes other components that are provided to thepatient 16, for example, electrolytes. A concentrate pump 46 and a valve48 are provided to selectively pump the concentrate from the concentratecontainer 44 to the regeneration loop 14. The concentrate contributes tothe regeneration of the dialysis solution in the regeneration loop 14.

[0126] Although the fluids in both the patient loop 12 and theregeneration loop 14 are, in an embodiment, recirculated continuouslythrough their respective loops, the various fluid pumps can becontrolled by a computer, processor, or microprocessor, collectivelyreferred to herein as a “controller” (not illustrated), to pump theirrespective fluids intermittently, if desired.

[0127] The dialysis system 10 in an embodiment is a closed, sterilesystem. Air, moisture and fluids from the environment around thedialysis system 10 cannot enter into the patient loop 12 or theregeneration loop 14. The dialysis system 10 does permit fluids (such asultrafiltrate) and air to exit the fluid loops 12, 14 and fluids (suchas concentrate) to be added to the fluid loops 12, 14 under controlledcircumstances. The dialysis system 10 is designed to preventuncontrolled contact of the patient and the regeneration loops 12 and 14with the surrounding environment.

[0128]FIG. 1 schematically shows an example of an gas separator 50 inthe dialysis system 10. The term “gas” is used herein to include gassesin general, including air, carbon dioxide (“CO₂”) and any other type ofgas that can become entrained in fluid loops 12 and 14. The regenerationfluid loops 12 and 14 can accumulate air for various reasons. Forexample, the fluid loops 12 and 14 may contain air prior to priming thesystem 10 with fluid or the storage containers may introduce air intothe fluid loops 12 and 14. The sorbent cartridge 32 may produce CO₂ andintroduce the CO₂ gas into the loops 12 and 14. The patient 16 can alsoproduce certain gasses, which become entrained in the dialysate andenter the loops 12 and 14.

[0129] It is desirable to remove gas from the fluid loops 12 and 14. Thegas separator 50 removes entrained gas from the fluid in theregeneration loop 14 and vents the gas to outside of the dialysis system10. In this manner, gas is purged from the regeneration loop 14. The gasseparator 50 includes a one-way vent, i.e., it permits gas to vent fromthe fluid loops 12 and 14 to the atmosphere but prevents gas outside ofthe fluid loops 12 and 14 from entering into the loops.

[0130] In one embodiment illustrated in FIG. 3, the gas separator 50 andthe sorbent cartridge 32 of FIG. 1 are combined into a single device102. One example of an gas separator 50/sorbant cartridge 32 combinationis shown in the patent application titled “Method and Composition forRemoving Uremic Toxins in Dialysis Processes,” Ser. No. 09/990,673,mentioned above. As illustrated in FIG. 1, however, the gas separator 50can be a separate system component or incorporated into systemcomponents other than the sorbent cartridge 32.

[0131] It is also desirable to purge gas from the patient loop 12. In anembodiment, an additional gas separator (not illustrated) can beprovided in the patient loop 12, which vents to the atmosphere. Inanother embodiment, the gas can be removed from the patient loop 12, fedto the gas separator 50 in the regeneration loop 14, e.g., via line 51,and vented to the atmosphere.

[0132] In an embodiment, one or more gas sensor(s) 52 are provided atdesired locations along the patient loop and/or the regeneration loop 14to detect gas in the system 10. In an embodiment, gas sensors 52electrically connect or are otherwise in communication with the systemcontroller, which monitors gas content in the loops 12 and 14. Thecontroller can control the system to perform any desired function inresponse to the gas, such as, stopping fluid flow, changing thedirection of fluid flow, or removing the gas. The gas separator 50 canbe any suitable device, which separates gas from fluid known to those ofskill in the art. Gas separators, such as the separator 50, can be usedwhich separate and vent the gas without being controlled by the systemcontroller. In an embodiment, the gas separator 50 absorbs the gasrather than venting it to the atmosphere as illustrated.

[0133] In an embodiment, the dialysis system 10 contains a fluid heater54, shown schematically in FIG. 1. The fluid heater 54 heats the fluidin the patient loop 12 to a desired temperature for supplying the fluidto the patient 16. The fluid heater 54 is an in-line heater (continuousflow heater) that heats the fluid to the desired temperature as thefluid flows continuously past the heater 54. In other embodiments,heaters other than in-line heaters can be used, for example, bulkheaters. The fluid heater 54 is shown in FIG. 1 in the patient loop 12at the fluid supply to the patient 16. However, the fluid heater 54 canbe positioned at other locations in the patient loop 12 and theregeneration loop 14, if desired. In another embodiment, one or both ofthe loops 12 and 14 include one or multiple heaters 54.

[0134] In an embodiment, the fluid heater 54 is a dual heater, includingan infrared heater 56 and a plate heater 58. An example of such a dualheater 54 is disclosed in a patent application entitled, “Medical FluidHeater Using Radiant Energy,” Ser. No. 10/051,609, incorporated hereinby reference. Both the infrared heater 56 and the plate heater 58 arein-line heaters that heat the medical fluid that flows continuously pastthe heaters 56, 58. The radiant energy or infrared heater 56 emitsinfrared energy that is directed to and absorbed by the fluid in thepatient loop 12, thereby heating the fluid. The radiant energy orinfrared heater 56 is a primary or high capacity heater which can heat arelatively large volume of cold fluid to a desired temperature in ashort period of time.

[0135] The plate heater 58 is a secondary or maintenance heater whichhas a relatively lower heating capacity relative to the infrared heater56. The plate heater 58 uses electrical resistance to increase thetemperature of a plate that in turn heats the fluid flowing near theplate.

[0136] The heater 54, which includes both high and low capacity heaters,provides an efficient heater design that accommodates various fluidheating requirements. For example, the radiant or infrared heater 56 isparticularly useful for quickly heating cool dialysate (high heat energydemand) that is supplied to the dialysis system 10, such as at theinitial system fill or if there is severe heat loss during dialysistreatment. The temperature of the dialysate at initial system fill canbe quite low, such as 5° C. to 10° C. if the fluid is stored in coldambient temperature.

[0137] The plate heater 58 is particularly useful to maintain a desiredtemperature (lower heat energy demand) of the fluid being supplied tothe patient, e.g., due to a normal amount of heat loss during dialysistreatment. The infrared heater 56 provides for the high heat demand in asmall amount of fluid exposure space, while the plate heater 58 providesfor maintenance heat demand and requires a lesser amount of input energycompared to the infrared or radiant heater 56. Furthermore, the heatingcapacity of the heater 54 is increased if both the infrared and plateheaters 56 and 58 are used together to heat the fluid.

[0138] The infrared heater 56 and the plate heater 58 can be arranged invarious configurations relative to each other. The heaters 56 and 58 inan embodiment are arranged so that the fluid passes by the heaterssequentially (e.g., first the radiant or infrared heater and then theplate heater). In another embodiment, the fluid passes by the heaterssimultaneously (both heaters at the same time) or in the reverse order.The fluid flow path past the heaters 56 and 58 can be a common flow pathfor both heaters 56 and 58 or include independent flow paths for eachheater 56 and 58. Besides radiant or infrared electrical resistanceheating, other types of heating such as convective, inductive, microwaveand radio frequency (“RF”) heating may be used.

[0139] In an embodiment, temperature sensors are provided at desiredlocations along one or both of the patient loop 12 and the regenerationloop 14. The temperature sensors monitor various fluid temperatures andare connected to the system controller to control the fluid temperatureswith the heater 54. When two or more heaters, such as the infraredheater 56 and the plate heater 58, are provided in the dialysis system10, the system 10, in an embodiment, can include separate temperaturesensors for each heater so that each heater can be controlledindividually.

[0140] The dialysis system 10 in an embodiment also includes variousother sensors to monitor various parameters. For example, fluid pressuresensors 60 and 62 are provided in the patient loop 12 of FIG. 1. Thefluid pressure sensors 60 and 62 electrically couple to or otherwisecommunicate with the controller to provide a signal that indicates therespective fluid pressure at that location. Based on the signals fromthe pressure sensors 60 and 62, the controller operates the fluid pumpsand valves to obtain and maintain desired fluid pressures in the loop 12running to and from the patient 16.

[0141] In an embodiment, the pressure sensors 60 and 62 are non-invasivepressure sensors. That is, the pressure sensors 60 and 62 do notphysically contact (and possibly contaminate) the medical fluid ordialysate. The pressure sensors 60 and 62 measure the medical fluidpressure and help to maintain a steady flow within the closed fluidsystem. Of course, other fluid devices, such as flow rate sensors,pressure gauges, flowmeters, or pressure regulators, which are notillustrated FIG. 1, may be provided in any suitable quantity and at anydesired location within either or both of the patient loop 12 and theregeneration loop 14.

[0142] In the illustrated embodiment, the system 10 includes an ammoniasensor 64. The ammonia sensor 64 measures the concentration of ammonia(NH3) and/or ammonium (NH4) in the fluid. Ammonia and ammonium areproduced by the regeneration sorbent cartridge 32 as a by-product of theurea catalysis urease. The ammonia and ammonium are normally removed bya cation exchanger in the sorbent cartridge 32. However, the dialysissystem 10 monitors the fluid for ammonia/ammonium concentrations withthe sensor 64 to confirm that the ammonia and ammonium are being removedand remain below safe threshold levels for the patient 16. The totalammonia and ammonium in solution is primarily determined by threeparameters: ammonia or ammonium, pH, and solution temperature. Bymeasuring these parameters (or adjusting a parameter, such as adjustingthe pH to a desired level), the total amount of ammonia and/or ammoniumin the dialysate can be determined.

[0143] One sensor 64 according to the present invention is described ina patent application entitled, “Ammonia and Ammonium Sensors,” Ser. No.10/024,170, incorporated herein by reference. The sensor 64 determinesthe total ammonia and ammonium content of an aqueous solution. Thesensor 64 includes a hydrophobic ammonia sensing membrane, a pHindicator or conditioner, a temperature sensor and an optical sensor. Analgorithm stored in the controller calculates the combined ammonia andammonium content from the three parameters (e.g., NH3, pH andtemperature). The ammonia gas, which is highly soluble in water, isquantified by the hydrophobic sensing membrane that changes color basedon the quantity of ammonia gas diffused into it. A multi-wavelengthoptical sensor continuously measures the membrane color through atransparent window. The sensor 64 achieves a non-intrusive measurementby the using the optical sensor to monitor color changes in thedisposable membrane placed inside the fluid path.

[0144] In the illustrated embodiment of FIG. 1, the dialysis system 10also includes one or more fluid flow measurement devices or volumesensors 66 that measure the volume of the medical fluid pumped eitherintermittently or cumulatively through one or both of the loops 12 and14. In an embodiment, the fluid flow measurement device 66 measures theamount of fluid supplied to the patient 16 by the patient loop 12.Additionally or alternatively, the regeneration loop 14 and/or theultrafiltrate drain line employ one or more fluid flow measurementdevices 66 to measure the amount of ultrafiltrate removed from thepatient 16. Various types of fluid volume measurement or flowratedevices can be used with the dialysis system 10, such as orifice plates,mass flow meters or other flow measuring devices known to those of skillin the art.

[0145]FIG. 1 schematically illustrates one embodiment of a flowmeasurement device or volume sensing device 66, which includes acapacitance sensor that measures the volume of fluid pumped through achamber, such as a pump chamber (dotted lines designating the device 66shown encircling the pumps 19, 24 and 30). The capacitive fluid sensor66 is disclosed in greater detail in the patent application entitled,“Capacitance Fluid Volume Measurement,” Ser. No. 10/054,487,incorporated herein by reference.

[0146] The capacitance C between two capacitor plates changes accordingto the function C=k×(S/d), wherein k is the dielectric constant, S isthe surface area of the individual plates and d is the distance betweenthe plates. The capacitance between the plates changes proportionallyaccording to the function 1/(R×V), wherein R is a known resistance and Vis the voltage measured across the capacitor plates.

[0147] In one embodiment of the capacitance sensor 66, the sensorcooperates with the pump chamber. The pump chamber in an embodimentincludes shells or walls defining a fixed and known volume and a pair offlexible membranes operating between the shells, which expand to fillwith fluid and contract to discharge fluid. The capacitance sensor 66includes capacitor plates disposed on opposite sides of the pumpchamber. As the volume of fluid in the chamber or fluid pump changes(i.e., the pump chamber fills or empties), the dielectric property ofthe varying fluids between the capacitance plates changes. For example,the combined dielectric constant of dialysate and air changes asdialysate replaces air (or air replaces dialysate) within shells of theconstant volume chamber. This change in the overall dielectric constantaffects a change in the capacitance between the two plates, which causesa change in voltage across the capacitance plates, wherein the change involtage can be sensed by a voltage sensing device. The controllermonitors the change in voltage by the voltage sensing device andcorrelates (after a calibration of the sensor) the capacitance change toan amount of fluid pumped through the chamber.

[0148] In another embodiment, the volume of the chamber or the pumpchamber can vary, e.g., by movement of one or both the shells of thechamber. In this embodiment, the capacitance between the capacitorplates changes due to a changing distance d between the plates and/or achanging surface area S of one or more of the plates, wherein thedielectric constant k is static because only one fluid resides at alltimes between the capacitor plates. In a further alternative embodimentof the measurement device 66, the capacitance C between the capacitorplates changes based on any combination or all three of a change indielectric constant k, distance d and surface area S.

[0149] The controller collects a multitude of voltage signals fromcapacitance changes from sensor 66 due to a plurality of chamber filland drain cycles, wherein the controller calculates a total volume ofmedical fluid pumped over a length of time or number of pump cycles. Thecapacitance sensor 66 monitors the medical fluid, e.g., dialysate, flowinto or from the pump chamber on a real time basis, and in a noninvasivemanner.

[0150] The capacitance sensor 66 enables the dialysis system 10 tomaintain the volume of fluid that is provided to the patient 16 atdesirable amounts and flow rates. Maintaining the fluid flow to thepatient 16 within desired levels is particularly advantageous forperitoneal dialysis therapies.

[0151] Also, it is desirable to maintain the fluid provided to thepatient at physiologic levels. Physiologic control, such as sensingand/or adjusting parameters of the fluids, can take place at variouslocations in the dialysis system 10, including the patient loop 12 andthe regeneration loop 14. For example, as mentioned above, the sorbentcartridge 32 may include a pH sensor that adjusts the fluid in theregeneration loop 14, which then adjusts the fluid in the patient loop12 via the dialyzer to be at a desired physiologic level.

Dual Lumen Connector

[0152] Referring now to FIG. 2, one embodiment of a dual lumen patientfluid connector 20 of the present invention is described in furtherdetail. As described above, the dual lumen connector 20 includes ahousing 70 having a lumen 72 for providing fluid to the patient lumenand a separate lumen 74 to remove fluid from the patient. Separatehousings each having one of the lumens 72 and 74 may be provided. Thepatient inflow lumen 72 connects to a patient inflow tube 76 of thepatient loop 12. Similarly, the patient outflow lumen 74 connects to apatient outflow tube 78 of the patient loop 12. A removable end cap 80is provided to seal a cavity 82 defined by the housing 70. The cavity 82surrounds or abuts the lumens 72 and 74 and provides a connection areafor the dual lumen catheter 22 (FIG. 1) to insert into the cavity 82 andmate with the lumens 72 and 74.

[0153] The housing 70, lumens 72 and 74 and the end cap 80, in anembodiment, are made of any material suitable for medical applications,such as plastic for example. In an embodiment, one of the lumens, e.g.,the patient inflow lumen 72 extends further into the cavity 82 than theother lumen, which helps facilitate mating of the connector 20 to thecatheter 22. In another embodiment both lumens 72 and 74 extend into thecavity 82 the same or different distance.

[0154] The dialysis system 10, particularly the patient loop 12, can beprimed, e.g., filled, with the end cap 80 in sealing engagement with thehousing 70. The arrows 84 and 86 figuratively illustrate therecirculating fluid flow through the dual lumen connector 20. The system10 can therefore run without a fluid connection to the patient. Also,the system 10 may include a patient by-pass line between the patientinflow and outflow tubes 76, 78 to allow fluid flow through the patientloop 12 while by-passing the patient 16. The end cap 80 is removed,e.g., pulled off or unscrewed, to expose the cavity 82 and the patientinflow and outflow lumens 72 and 74, respectively, for connection to thedual lumen catheter 22.

[0155] In an alternative embodiment, the patient fluid loop 12 directlyconnects to the dual lumen catheter 22 or to two separate single lumencatheters. In a further alternative embodiment, the connector 20 isadapted to connect to two separate single lumen catheters. In yetanother alternative embodiment, two separate connectors link singlelumen catheters to incoming and outgoing lines of the patient fluid loop12. Other configurations are also contemplated by the present invention.

Alternative Dual Loop System with Balanced Flow

[0156] Referring now to FIG. 3, a system 100 for providing dialysistreatment to a patient is illustrated. The system 100 of FIG. 3 includesmany of the same components as the system 10 of FIG. 1. For example, thesystem 100 includes two loops, a patient loop 12 and a regeneration loop14. The patient loop 12 passes a medical fluid, dialysate or blood, toand from a patient 16. In a peritoneal dialysis embodiment, the patientloop 12 and regeneration loop 14 are initially filled and primed withdialysate from a dialysate bag 18. The patient loop 12 fluidly connectsto the patient 16 by the multi-lumen patient fluid connector 20described above in connection with FIG. 2. In a peritoneal dialysisembodiment, the multi-lumen connector 20 connects to a dual lumencatheter 22. In a hemodialysis embodiment, the patient loop 12 fluidlyconnects to a multi-lumen hemodialysis needle or other patient bloodaccess device.

[0157] The system 100 includes multiple patient fluid pumps 24 a and 24b. It has been found that using multiple pumps, such as the patientfluid pumps 24 a and 24 b, creates a steadier flow of fluid to and fromthe patient 16 within the patient loop 12. For example, fluid may beexiting the fluid pump 24 a while the fluid pump 24 b is filling withfluid. Balance chambers can be provided, in an embodiment, to balancefluid flow.

[0158] The system 100 includes the dialyzer 26 having the dialyzermembrane 28. The spent dialysate (or blood in a hemodialysis embodiment)laden with waste and excess water in the patient fluid loop 12 iscleaned or regenerated when recirculated through the dialyzer 26. Thewaste passes from the patient loop 12 across the dialyzer membrane 28 tothe regeneration loop 14. In the regeneration loop 14, the fluid pumps30, 30 continuously pump the regenerating dialysate through thecombination device 102, which includes the absorbent cartridge 32 andthe gas separator 50. The system 100 includes dual dialysate fluid pumps30 to provide balanced flow within the regeneration loop 14. That is,one of the fluid pumps 30 is being emptied of fluid while the other pump30 is being filled with fluid. In an embodiment, balance chambers can beprovided for balancing fluid flow.

[0159] The system 100 can drain ultrafiltrate and other fluids into thedrain bag 38. An ultrafiltrate pump 19 pumps the ultrafiltrate andfluids from the patient loop 12 or the regeneration loop 14, for examplethrough valves 40 and 42, into the drain 38. The system 100 alsoprovides the ability to collect fluid in a twenty-four hour collectionbag 39 for evaluation of the dialysis therapy.

[0160] In an embodiment, one of the patient fluid pumps 24 a or 24 bpulls dialysate fluid from either the dialysate bag or container 18 orthe last bag 21. The last bag 21 includes a volume of fluid that isplaced in the patient's peritoneal cavity just prior to the end of thedialysis treatment. The patient with the dialysate from the last bag 21in the peritoneal cavity disconnects from the system 100 and is able toperform daily activities. The next dialysis therapy begins with drainingthe last bag from the patient.

[0161] The system 100 includes a concentrate container 44, a concentratepump 46 and valves 48. The concentrate pump 46 provides concentrate fromthe concentrate container 44 to the regeneration loop 14, for exampleinto the fluid line exiting from the outlet 36 of the combinationabsorbent cartridge and vent 102. The concentrate container 44 suppliesnecessary compounds, such as electrolytes and osmotic agents, to theregeneration loop 14 of the system 100 to maintain the desiredconcentrations of those components.

[0162] Besides the concentrate that is contained in the concentratecontainer 44, the system 100 regenerates dialysate through theregeneration loop 14 and does not require fluids from an outside source.Hence the system 100, as are each of the systems described herein, iscompletely closed to the outside. The systems of the present inventionare thus “closed loop systems”. The closed loop nature of the patientloop 12 and the regeneration loop 14 enables the loops to runcontinuously without absorbing or gathering outside contaminants. Theclosed loop systems of the present invention also maintain sterility bypreventing contamination from the environment.

[0163] The system 100, like the system 10, may generate gases over time,such as air and CO₂. The system 100 provides a plurality of gas sensors52 that detect the various gases that may be in the system 100. In thesystem 100, the gas sensors 52 are provided at an air separator whichseparates gas from the fluid in the patient loop 12. A gas separationline 51 feeds the separated gas from the patient loop 12 to the inletside 34 of the combination absorbent cartridge and gas separator device102. The gas is then purged out of the system 100 by the gas separator50. The gas separator 50 maintains the closed loop structure of thesystem 100 by preventing contaminants from entering the system 100. Forexample, the gas separator 50 can include a microbial filter whichallows gas to exit the system 100, but prevents contaminants fromentering the system 100. In another embodiment, the gas from the patientloop 12 may be purged from the system 100 by a separate gas purge deviceat the patient loop 12. The gas sensors 52, in an embodiment, can sendan electronic signal to the controller (not illustrated). When thecontroller detects gas, the controller causes one or more valves toopen, wherein the gas from the loop 12 is fed to a one-way vent andpurged from the system 100.

[0164] The system 100 further includes the inline heater 54, which, inan embodiment, includes an infrared or radiant heater 56 and a plateheater 58 as described above. In an embodiment, the heater 54 has an airseparator which allows air to exit port 59 on be purged from the system.

[0165] The system 100 further includes an orifice device 61 thatstabilizes the differential pressure in the dialyzer 26 across themembrane 28. That is, the orifice device 61 can restrict the flow in thepatient loop 12 to create a pressure differential between the patientside and regeneration side of the dialyzer 26. The pressure gradient ordifferential occurs across the membrane 28 in which the patient loop 12having a higher fluid pressure than the regeneration loop 14. Theorifice device can be a fixed or variable flow restriction and canprovide a fixed or variable pressure differential. Also, the orificedevice 61 can be electrically coupled to and operated by the controller,which can activate, e.g., open or close the orifice device as necessary.

[0166] The pressure differential across the membrane 28 (higher pressurein the patient loop 12 and lower pressure in the regeneration loop 14)created by the orifice 61 assists in maintaining a greater pressure inthe regeneration loop 14 relative to atmosphere pressure external to thesystem 100. The positive pressure in the regeneration loop 14 relativeto the external atmosphere pressure aids in ensuring that external airis not pulled from the surrounding environment through the air vent 50into the regeneration loop 14, i.e., air can only exit the system 100and not enter into the system 100. Accordingly, the orifice 61contributes to the closed loop nature of the system 100.

[0167] The system 100 provides a number of temperature sensors, such assensors 63, 65 and 67, which monitor temperatures at various pointswithin the patient loop 12. The controller uses the sensed temperaturesto maintain a desired temperature within the patient loop 12. Asillustrated, the temperature sensor 63 is located at or on the heater54, which enables the system 100 to sense a temperature at a point veryclose to the constituent heaters 56 and 58, and to control the heaters56, 58.

[0168] The system 100 further includes one or more pressure sensors 60and 62, which reside at various points along the patient fluid loop 12.The pressure sensors 60 and 62 can be used to prevent excessive positiveor negative pressures from being applied to the patient. The pressurewithin the system can be controlled by, e.g., activation of the patientfluid pumps 24 a, 24 b.

[0169] The system 100 also monitors the absorbent cartridge 32 with anammonia/ammonium sensor. Sample fluid exiting the absorbent cartridge 32can be directed through a pH adjuster 71 to force the ammonia/ammoniumequilibrium balance to a particular level. The amount of ammonia and/orammonium in the sample fluid is measured by a sensor 73. Accordingly,the effectiveness of the cartridge 32 to remove ammonia/ammonium afterconversion from urea can be monitored. When the concentration of ammoniaand/or ammonium reaches a threshold level, the system can produce asignal, or take other action such as shutting down, that indicates thecartridge 32 needs to be replaced.

[0170] Of course, the system 100 can monitor other fluid parameters andtake appropriate action, as desired. Also, sample fluid can be taken atany desired location in the system 100. Further, fluids in the patientand regeneration loops 12, 14 can be tested or monitored directly ratherthan taking samples.

[0171] The system 100 also includes fluid volume sensors 66 which in anembodiment are capacitance sensors that sense a change in capacitanceoccurring between two capacitor plates. The capacitor plates surroundthe pumps 24 of the patient loop 12, the pumps 30 of the regenerationloop 14 and the pumps leading to the fluid containers. Each of the pumps24 a, 24 b, pump 30, pump 19 and pump 46 can be provided with thecapacitance volume sensor 66 of the present invention. Each of thesensors 66 sends a discrete signal to the controller (not illustrated),which measures and monitors the volume of fluid flowing through the pumpchambers of the respective pumps. In other embodiments, any suitablefluid volume measurement device can be used.

Alternative Dual Loop System with Gas Separation

[0172] Referring now to FIG. 4, a system 110 of the present invention isillustrated. The system 110 of FIG. 4 is similar to the system 100 ofthe FIG. 3 and is a closed loop system. The system 110 includes variouscomponents of the system 100 described previously. The system 110 has aregeneration loop 14 which has a pair of balanced dialysate fluid pumpscreated by a pair of chambers 75 that operate with the pumps 30. Eachbalance chamber 75 includes a pair of chambers separated by a membrane.When one of the pumps 30 fills one side of the chambers of the balancechambers 75 fills with medical fluid, the membrane is forced toward theother chamber, which forces fluid out of that chamber. In this way, themembrane acts to balance the flow of the dialysate fluid within theregeneration loop 14, so that there is no net flow of fluid across thedialyzer membrane except for the flow needed to replace the fluidremoved by the ultrafiltrate pump 19.

[0173] Another difference of the system 110 of FIG. 4 compared to thesystem 100 of FIG. 3 is the gas separator 50. The gas separator 50 inthe illustrated embodiment of the system 110 is independent of thesorbent cartridge 32. The gas separator 50 accepts gas through a ventline 51 that runs from the exit port 59 of the heater 54 in the patientfluid loop 12. One or more gas sensors 52 monitor gas in the vent line51 as illustrated.

Disposable Cassettes

[0174] Referring now to FIG. 5, a dialysis system having a disposablecassette 120 according to the present invention is illustrated. In thisvariation of the system 100 of FIG. 3, the pumps 30 of system 120 drawfluid from accumulators A4 and A6 and discharge into accumulators A3 andA5. Accumulators A3 to A6 smoothen the dialysate flow by dampeningpressure fluctuations during pumping. In an embodiment, much of the flowlogic and at least parts of the flow devices described above areprovided in the disposable cassette 120. The cassette 120, in anembodiment, has a rigid plastic body 122 with various fluid flowchannels and fluid chambers defined in the body 122. A flexible membraneis bonded to the front side of the cassette body 122 shown in FIG. 5.The membrane covers the fluid channels and chambers and is sealed to thebody 122 around the channels and chambers. Accordingly, the membraneforms a wall of the fluid flow paths and fluid chambers. Similarly, theback side of the cassette body 122 may also be covered with a membrane.

[0175] The body 122, in an embodiment, is approximately 12 inches high,eight inches wide, and one inch deep. The flow components and flow linesdefined by the body 122 fluidly connect to other system components.Also, pump actuators, valve actuators, sensors and other systemcomponents may interface with the cassette 120.

[0176] Specifically, the body 122 provides a portion of the closedpatient the regeneration loops 12 and 14. The dual lumen catheter 22that inserts into the peritoneal cavity of the patient 16 connects tothe dual lumen connector 20 outside of the body 122 of the disposablecassette 120. The patient loop 12 extends from an exit port 124 of thedialyzer 26 to a valve chamber 126 defined by the body 122. The patientfluid loop 12 includes a series of manifolds and fluid flow paths thatfluidly connect to the patient fluid pump(s) 24. The patient fluid pump24 pumps the dialysate through the patient 16 and into an inlet 128 ofthe dialyzer 26.

[0177] The patient fluid loop 12 also connects via pathways defined bythe body 122 of the disposable cassette 120 to various medical fluidbags. For instance, the dialysate fluid bag 18, which is maintainedoutside of the disposable cassette 120, fluidly connects to a line 130leading to the patient fluid loop 12. Similarly, the last bag 21 alsoconnects via a line defined by the body 122 to the line 130 that fluidlycommunicates with the patient fluid loop 12. The line 130 defined by thebody 122 also fluidly communicates with the ultrafiltrate drain 38.

[0178] The body 122 of the disposable cassette 120 also defines chambersfor the concentrate pump 46 and the ultrafiltrate pump 19. Theconcentrate pump 46 fluidly connects to an external concentrate bag 44.The twenty-four hour collection bag 39 described above fluidly connectsalong with the drain 38 to a fluid line defined by the body 122 thatruns to the ultrafiltrate pump 19.

[0179] The disposable cassette 120 provides fluid flow paths and defineschambers and other types of fluid orifices for the fluid flow componentsdescribed above. Specifically, the body 122 of the disposable cassette120 defines a patient fluid pump chamber 24 and dialysate fluid pumpchambers 30. The disposable cassette 120 mounts to a separatenon-disposable housing that includes the mechanical workings of the flowcomponents, such as the pumps. The pump chambers are bounded on one sideby a flexible membrane (not illustrated) that is positioned adjacent toand driven by the pump plungers of the non-disposable housing.

[0180] At least one side of the cassette 120 is covered with theflexible, e.g., plastic membrane (not illustrated). The disposablecassette 120 plugs into a cavity or portion of the non-disposablehousing (not illustrated). The housing provides the actuators for eachof the pumps herein described, e.g., the patient pumps 24, the dialysatepumps 30, the ultrafiltrate pump 19 and the concentrate pump 46. Thehousing also provides the actuators for the various valve chambersdefined by the body 122 of the cassette 120, e.g., valve chamber 126.The more expensive mechanical and electromechanical pieces of the flowcomponents, e.g., the pump actuators and valve actuators, are kept andreused in the housing.

[0181] The disposable cassette 120 provides sterile, disposable fluidpathways, such as the pump chambers and the valve chambers. Theactuators of the non-disposable housing press against the flexibleplastic membrane at the pump chambers and valve chambers to force orallow fluid through the system. When the pump actuator pulls back frompressing against the membrane, the membrane returns to its normal shapeand no longer exerts a force on the fluid within the pump chamber. Thepump chamber fills with fluid as the membrane is drawn back. Also, themembrane can be positively drawn back by, for example, the pump actuatoror vacuum pressure. The pump has thus made a cycle.

[0182] The body 122 of the disposable cassette 120 also defines at leasta portion of a mounting area for housing the ammonia, ammonium or pHsensors or adjustors. In the illustrated embodiment, the disposablecassette 120 defines an area for housing the pH adjustor 71 and adisposable colormetric membrane (which changes color based on theammonia/ammonium concentration) of the ammonia/ammonium sensor 73,wherein the fluid within the body 122 of the cassette 120 can fluidlycommunicate with the sensor. The optical color reader of theammonia/ammonium sensor 64 is disposed in the non-disposable housing(not illustrated), wherein the sensor can receive electrical power asneeded. If a pH sensor is used instead of the pH adjustor 71, a reusableportion of the pH sensor can also be located in the housing.

[0183] The housing also provides the in-line heater 54 and in anembodiment provides one of either the radiant heater 56 and the plateheater 58, which is described in detail in the patent applicationentitled, “Medical Fluid Heater Using Radiant Energy,” Ser. No.10/051,609, mentioned above. Further, the housing provides one of thecapacitor plates of the fluid volume sensor 66 beneath one or more ofthe pump actuators, as described in detail in the patent applicationentitled, “Capacitance Fluid Volume Measurement,” Ser. No. 10/054,487,mention above.

[0184] Referring back to the cassette 120 of FIG. 5, the cassette 120has an in-line heating fluid heating path 123 for heating the fluid. Thefluid in the heating path 123 is heated by a heater external to thecassette.

[0185] The cassette 120 also has one or more gas separators 125 whichseparate gas from fluid in the cassette 120. The gas separators 125 feedthe separated gas through a line 127 to a vent 129.

[0186] The closed loop system of the present invention enables at leastone waste component to pass through the membrane 28 of the dialyzer 26from the patient fluid loop 12 to the regeneration loop 14. The patientloop 12 extending outside of the body 122 fluidly connects to a valvechamber 132 defined by the body 122. The regeneration loop 14 includesmanifold sections defined by the body 122 and leads to pump chambers 30.The closed loop system prevents air or other fluids from entering thesystem.

[0187] The pump chambers 30 fluidly communicate with the sorbentchemical cartridge 32 and the gas separator 50 of the combined device102. The regeneration loop 14 extends from the outlet 36 of the combineddevice 102 and returns to the body 122 of the disposable cassette 120through the valve chamber 134. From the valve chamber 134, theregenerated dialysate is pumped through the pump chambers 30 and intothe manifold system defined by the body 122.

[0188] Referring now to FIG. 6, another closed loop system havinganother disposable cassette 140 is illustrated. This embodiment of thedisposable cassette 140 of the present invention includes many of thesame flow components and flow chambers as the cassette 120 of FIG. 5.The cassette 140, however, only includes a single regeneration pump body30. The cassette 140 in general, is less complicated than the cassette120 and illustrates that the disposable cassettes of the presentinvention may be adapted for different embodiments of the closed loopdialysate regeneration systems described herein.

[0189] Like the cassette 120 of FIG. 5, at least one side of thecassette 140 is covered with a flexible, e.g., plastic membrane (notillustrated). The disposable cassette 140 plugs into a non-disposablehousing (not illustrated) that provides the actuators for the variouspumps, e.g., the patient pump 24, the dialysate pump 30, theultrafiltrate pump 19 and the concentrate pump 46. The housing alsoprovides the actuators for the various valve chambers defined by thebody 122 of the cassette 140. The more expensive mechanical andelectromechanical pieces of the flow components, e.g., the pumpactuators, are again kept and reused in the housing. As described above,the actuators press against the flexible plastic membrane at the pumpchambers to force fluid through the system.

[0190] As illustrated in both FIGS. 5 and 6, the disposable cassette 120or 140, in combination with certain external devices such as thedialyzer 26, sorbent cartridge and gas separator device 102 and the filland drain bags, provides completely closed loop systems. The onlymake-up or additional fluid that the regeneration system uses is that ofthe concentrate from the concentrate bag 44, which seals to a devicewithin the body 122 of the cassettes 120 and 140. Also, other than thesystems being connected to a patient, fluids and air cannot enter theclosed loop system.

[0191] Referring now to FIG. 7, a schematic diagram illustrates thedifferent physical components of a disposable set of the regenerationsystems of the present invention. The disposable set is intended to beused for a single dialysis therapy and then discarded. Anotherdisposable set is used for the next dialysis therapy. Each of theabove-described systems 10, 100 and 110 in an embodiment includes adisposable cassette, such as the cassette 120 or 140. The disposablecassette 120 or 140 provides a port 141 that connects to the concentratebag 44 via a line 147. The cassette provides a port 142 that fluidlyconnects to the drain bag 38 via a line 148. The cassette provides aport 143 that fluidly connects to the last bag 21 via a line 149. Thecassette defines a port 144 that fluidly connects to the dialysate bag18 via a line 150. The cassette provides ports 145 and 146 that run toand from the dual lumen connector 20 via patient lines 151 and 152,respectively.

[0192] In an embodiment, each of the lines 147 to 152 are made ofmedical grade tubing, such as a flexible, sterile and inert plastic suchas polyethylene, polystyrene, polypropylene or polyvinylchloride(“PVC”). In an embodiment, the bags and the lines are clear so that thepatient or operator can see fluids traveling from the bags and throughthe lines to a cassette 120 or 140. The lines 147 to 152 connect to theports 141 to 146 via any type of medical fluid connection known to thoseof skill in the art. In an embodiment, the connections are quick-typeconnections that enable the patient or operator to easily remove theline from its mating port.

[0193] The disposable cassette 120 or 140 includes at least one port 153that fluidly connects to at least one outlet port 154 of the gasseparator 50 or combination device 102. The disposable cassette 120 or140 includes at least one port 155 that fluidly connects to at least oneinlet port 156 of the sorbent cartridge 32 or combination device 102.The lines connecting the disposable cassette 120 or 140 to the sorbentcartridge 32, gas separator 50 or combination device 102 including sameare made of medical grade tubing, such as a flexible, sterile and inertplastic such as polyethylene, polystyrene, polypropylene or polyvinylchloride.

Alternative Dual Loop System

[0194] Referring now to FIG. 8, an alternative closed loop regenerativesystem 160 is illustrated. The system 160 is shown schematically,however, the system 160 may employ the disposable set described abovesuch as the disposable cassette, the fluid pumps, the various sensors,valves and controller. The system 160 includes a patient fluid loop 12and a regeneration loop 14.

[0195] When dialysate is removed from the peritoneal cavity of thepatient 16, the solution passes through an activated charcoal and anionexchanger 162. The activated charcoal of the filter or exchanger 162removes uric acid, creatinine, small molecular weight organics andmiddle molecules. The anion exchange column of the exchanger 162 removesphosphate. The solution exiting the filter or exchanger 162 enters asolution or dialysate bag 18. The dialysate entering the solution bag 18has two possible places to exit. One possibility includes exiting thesolution bag 18 from a port 163, entering a filter 166 and returning tothe peritoneal cavity of the patient 16. Another possibility includesexiting the solution bag 18 at a port 165 and entering a nanofilter 164.The system 160 splits the dialysate fluid exiting the solution bag orcontainer 18.

[0196] The nanofilter 164 operates similar to the dialyzer 26 describedabove. The nanofilter 164 includes a membrane. The membrane of thenanofilter 164 rejects most electrolytes, i.e., allows most of theelectrolytes to return to the solution bag. The nanofilter 164, however,filters most all of the urea and a small amount of sodium through themembrane and into a sorbent system cartridge 32, which is similar to thesorbent cartridges described above. The sorbent cartridge 32 asdescribed above absorbs and the urea from the fluid that is able topermeate through the membrane of the nanofilter 164.

[0197] A plurality of pumps (not illustrated) are provided toindividually circulate medical fluid or dialysate through the patientloop 12 and the regeneration loop 14. The pump or pumps that control therecirculation through the regeneration loop 14 are adapted to circulatethe regenerating fluid at a different flow rate, i.e., much faster, thanthe flow rate of fluid pumped through the patient loop 12. It isbelieved that by using this method, the need for a concentration bagsuch as the concentration bags 44 described above would not be needed.Thus, it should be appreciated that the system 160 is a closed loopsystem that does not require any sort of make-up materials or anycontinuous source of outside fluid. The system 160 is therefore veryadept at keeping air and other contaminants from entering the system.

[0198] In an alternative embodiment, the a reverse osmosis membrane oran electrooxidation system replaces the sorbent cartridge 32. In thisalternative embodiment, a reconstitution or concentration bag, such asthe concentration bag 44, is likely to be necessary.

[0199] The regeneration loop 14 removes urea at a rate of approximately50 to 80%. The dialysate returns to the peritoneal cavity of the patient16 substantially free from uric acid, creatinine, small molecular weightorganics and middle molecules. Further, the nanofilter 164 can rejectcalcium magnesium at a rate of approximately 98% and glucose at a rateof approximately 80%. The permeate stream exiting the nanofilter 164includes urea, approximately 70% sodium chloride and approximately 20%glucose. It should be appreciated that the system 160 is useful forperforming continuous flow peritoneal dialysis.

Dual Loop System for Hemodialysis

[0200] Referring now to FIG. 9, a system 170 is illustrated. Each of theprevious systems 10, 100 and 110 of FIGS. 1, 3 and 4, respectively, canbe used for peritoneal dialysis or hemodialysis. However, each of thesystems described above has been primarily described and illustratedusing peritoneal dialysis, that is, the patient loop has beenillustrated using a dialysis solution. The system 170 illustrates thatthe dual lumen catheter or two single lumen catheters can be replaced bya hemodialysis needle 171, which connects to the arm (or other suitableportion) of the patient 16 to withdraw blood through the hemodialysisneedle 171.

[0201] The system 170 illustrates that the patient's blood flows throughthe patient loop 12 while dialysate flows through the regeneration loop14. The patient's blood flows along one side of the membrane 28 of thedialyzer 26, while the dialysate flows along the outside or other sideof the membrane 28 of the dialyzer 26. The waste components andultrafiltrate transfer from the patient's blood in the patient loop 12,through the membrane 28, into the dialysate in the regeneration loop 14.

[0202] The system 170 includes a fixed volume recirculating regenerationloop 14 that dialyzes the patient fluid loop 12. A single pump 172operates to remove the ultrafiltrate from the patient 16 to theultrafiltrate container 38. The pump 172 adds dialysis fluid from thedialysis bag 18 or concentrate from the concentrate bag 44 to theregeneration loop 14. In an alternative embodiment, the concentrate canbe metered into the dialysate of the regeneration loop 14 as a solidprior to or during therapy.

[0203] As an alternative to the capacitance volume sensing describedabove, the volume of dialysate fluid flowing through the regenerationloop 14 can be determined using an electronic balance 174 illustratedbelow the dialysate bags. The electronic balance 174 keeps track of theamount of dialysate that is supplied to the system during a priming ofthe system. The electronic balance 174 also monitors any additionaldialysate added to the patient loop 12 during dialysis treatment. Theelectronic balance 174 measures the amount of ultrafiltrate that iswithdrawn from the system and the amount of the concentrate that isadded from the concentrate bag 44. In other alternative embodiments, anyof the systems described herein can be sensed using other types offlowmeters or devices employing Boyle's Law known to those of skill inthe art.

[0204] The system 170 removes ultrafiltrate by opening a valve chamberand transferring a known volume of the fluid into the ultrafiltrate bag38. The removal of fluid creates a pressure differential across themembrane 28 of the dialyzer 26, which causes fluid to filter through thedialyzer membrane 28 and into the regeneration circuit 14. Steriledialysate from a supply bag 18 is infused into the patient circuit 12 asrequired. Concentrate from the concentrate bag 44 can also be infusedinto the regenerating circuit 14 as needed. Pressure sensors 176 monitorand control the rate at which the system 170 draws ultrafiltrate intothe container 38.

[0205] Gas sensors 52 are used to prevent air from being delivered tothe patient 16. In an embodiment, a multi-analyte sensor 178 is employedto monitor the concentration of electrolytes in the regenerateddialysate as well as the efficiency of the regeneration system inremoving uremic toxins. The output of the multi-analyte sensor 178controls the rate of reconstitution from the concentrate bag 44, theefficiency of the regeneration system and can detect the presence of aleak in the dialyzer. A vent 180 vents air that becomes trapped in thesystem or CO₂ that is generated by the absorbent cartridge 32. In analternative embodiment, an automated valve that is provided integrallywith the adsorbent cartridge 32 replaces the mechanical vent 180.

[0206] Although the system 170 is illustrated as a hemodialysis system,the system 170 is easily converted to a peritoneal dialysis system byplacing the catheter into the patient's peritoneal cavity and by runningdialysate through the patient loop 12 as opposed to the patient's blood.The ultrafiltrate bag 38, the dialysate container 18 and the concentratecontainer 44 each fluidly connect to the regeneration loop 14 and thepatient circuit is kept relatively simple. The system 170 is especiallyconducive for continuous flow of peritoneal dialysis, however, standardAPD and TIDAL therapies could be performed in the system 170.

Multi-Purpose Container

[0207] Referring now to FIG. 10, a combined absorbent cartridge, pumpand valve system is placed into a single container, e.g., a canister,cartridge or cassette 190. The combination container 190 is illustratedas housing the components specifically described in the system 170 ofFIG. 9. However, the combination container 190 is adaptable to house thecomponents of any of the above-described systems, namely, the systems10, 100 and 110. The canister, cartridge or cassette is adaptable to bemade of any material such as plastic or metal. The container 190includes the adsorbent cartridge 32, which is configured as describedabove. Alternatively, the container includes the combination device 102that provides the adsorbent cartridge 32 and the gas separator 50.

[0208] The container 190 includes the pumps illustrated in FIG. 9including the pump 172 that enables dialysate to be drawn from thedialysate bag 18 or concentrate to be drawn from the concentrate bag 44.Additionally, the pump 172 enables ultrafiltrate to be drained into thebag 38. In an embodiment, the container 190 includes the multi-analytesensor 178 and the gas sensor 52, as described in the system 170 of FIG.9. The container 190 also includes the mechanical or automated vent 180described in the system 170. Thus, the only devices external to thecontainer 190 are the dialysate bags and the hemodialysis needle 171that is inserted in the patient's arm or other extremity to performhemodialysis. Obviously, by the multi-lumen connector 20 and catheter 22can replace the needle 171 to perform peritoneal dialysis.

[0209] When the container 190 is provided in the form of a disposablecassette, the cassette 190, like the cassettes 120 and 140 of FIGS. 5and 6, is covered on at least one side with a flexible, e.g., plasticmembrane (not illustrated). The disposable cassette 190 plugs into anon-disposable housing that provides the actuators for the variouspumps, e.g., the patient pumps 24, the dialysate pumps 30, theultrafiltrate pump 19 and the concentrate pump 46. The more expensivemechanical and electromechanical pieces of the flow components, e.g.,the pump actuators, are again kept and reused in the housing. Thesorbent cartridge 32 and the gas vent 180 can be disposable.

[0210] The above specification has been broken down into headings forpurposes of readability, clarification and to promote the enablement ofthe present invention. The headings are in no way intended to limit thecombined teachings of the present invention. The features taught underany given heading are not limited to the embodiments disclosed under theheading. The present invention includes any combination of features fromthe disclosures under the different headings provided herein. Further,while the presently preferred embodiments have been illustrated anddescribed, numerous changes and modifications can be made withoutsignificantly departing from the spirit and scope of this invention.Therefore, the inventors intend that such changes and modifications arecovered by the appended claims.

The invention is claimed as follows:
 1. A system for providing dialysiscomprising: a patient fluid loop including a first pump and multiplepatient lumens; a second fluid loop including a second pump and amedical fluid regenerator; a membrane device in fluid contact with andseparating the patient fluid loop and the second fluid loop, themembrane device allowing at least one selected component of the fluid inthe patient fluid loop to transfer to the second fluid loop; the secondloop being closed except for the transfer of the selected component viathe membrane device; and a controller that operates the first and secondpumps to recirculate fluid in the patient loop and the second loop. 2.The dialysis system of claim 1, wherein the membrane device is adialyzer.
 3. The dialysis system of claim 1, wherein a pressure gradientexists across the membrane device.
 4. The dialysis system of claim 1,wherein the patient loop is closed except for the transfer of theselected component via the membrane device.
 5. The dialysis system ofclaim 1, wherein the membrane device includes a nanofilter which allowsurea to pass from the patient fluid loop to the second fluid loop. 6.The dialysis system of claim 1, wherein the medical fluid regeneratorincludes a uremic toxin sorbent.
 7. The dialysis system of claim 1,wherein the medical fluid regenerator includes at least one of: urease,zirconium phosphate, zirconium oxide, and carbon.
 8. The dialysis systemof claim 1, which includes a gas separator that removes gas from atleast one of the patient and second fluid loops.
 9. The dialysis systemof claim 8, wherein the gas separator and the medical fluid regeneratorare provided in a single device.
 10. The dialysis system of claim 1,which includes a gas vent that vents gases from the patient and secondfluid loops.
 11. The dialysis system of claim 1, wherein the secondfluid loop includes a multi-analyte sensor that monitors a concentrationof electrolytes in the medical fluid.
 12. The dialysis system of claim1, wherein peritoneal dialysis fluid is circulated through the patientfluid loop.
 13. The dialysis system of claim 1, wherein blood iscirculated through the patient fluid loop.
 14. The dialysis system ofclaim 1, wherein at least parts of the patient fluid loop and the secondfluid loop are provided in a disposable device.
 15. The dialysis systemof claim 1, wherein the second fluid loop includes a balance chamberthat balances flow within the second fluid loop.
 16. The dialysis systemof claim 1, wherein the controller enables fluid to flow in oppositedirections through the multiple patient.
 17. The dialysis system ofclaim 1, which includes a dual lumen catheter that defines the multiplepatient lumens.
 18. The dialysis system of claim 1, wherein at least oneof the patient fluid loop and the second fluid loop includes an in-linefluid heater.
 19. The dialysis system of claim 18, wherein the in-linefluid heater includes a radiant heater and a plate heater.
 20. Thedialysis system of claim 1, which includes at least one medical fluidsensor that senses at least one indicator selected from the groupconsisting of: ammonia, ammonium and pH.
 21. The dialysis system ofclaim 1, which includes a fluid volume sensor in at least one of thepatient and second fluid loops.
 22. The dialysis system of claim 21,wherein the fluid volume sensor includes a capacitance fluid volumesensor that uses a chamber in fluid communication with the at least onefluid loop.
 23. The dialysis system of claim 22, wherein the chamber isa pump chamber.
 24. The dialysis system of claim 1, which includes anultrafiltrate container in fluid communication with at least one of thepatient and second fluid loops.
 25. The dialysis system of claim 1,which includes a fluid concentrate container in fluid communication withat least one of the patient and second fluid loops.
 26. The system ofclaim 1, wherein the controller operates the first pump continuously topump fluid into and out of a patient.
 27. A disposable dialysis cassettecomprising: a flexible membrane covering a patient pump chamber and aregeneration pump chamber; means for fluidly connecting the patient pumpchamber to a closed loop patient fluid path; and means for fluidlyconnecting the regeneration pump chamber to a closed loop regenerationfluid path, wherein the patient path fluidly communicates with theregeneration path via a dialyzer.
 28. The disposable dialysis cassetteof claim 27, which defines a fluid path that fluidly communicates with adialysate sorbent cartridge.
 29. The disposable dialysis cassette ofclaim 27, which defines a fluid path that fluidly communicates with agas separator.
 30. The disposable dialysis cassette of claim 27, whichdefines a fluid path that fluidly communicates with a dialysisconcentrate container.
 31. The disposable dialysis cassette of claim 27,which defines a fluid path that fluidly communicates with a dialysatelast bag.
 32. The disposable dialysis cassette of claim 27, whichdefines a fluid path that fluidly communicates with a dialysate bag. 33.The disposable dialysis cassette of claim 27, which defines a fluid paththat fluidly communicates with a drain container.
 34. The disposabledialysis cassette of claim 27, which defines a fluid path that fluidlycommunicates with a patient fluid connector.
 35. A dialysis therapydevice for use with a disposable cassette, the device comprising: ahousing having a portion that receives the disposable cassette; apatient pump actuator in the housing that pumps fluid through a patientpath defined at least in part by the disposable cassette; and aregeneration pump actuator in the housing that pumps fluid through aregeneration path defined at least in part by the disposable cassette.36. The dialysis therapy device of claim 35, which includes at least onefluid volume measurement sensor component that cooperates with at leastone of the patient pump actuator and the regeneration pump actuator. 37.The dialysis therapy device of claim 35, wherein the housing houses afluid heater.
 38. The dialysis therapy device of claim 35, wherein thehousing houses at least one sensor selected from the group of: anammonia sensor, an ammonium sensor and a pH sensor.
 39. The dialysistherapy device of claim 35, wherein the housing houses at least onevalve actuator that operates with the disposable cassette.
 40. A methodof moving fluid in a dialysis system comprising the steps of:continuously recirculating a first fluid through a patient loop;continuously recirculating a second fluid through a regeneration loop;transferring at least one waste component from the patient loop to theregeneration loop through a device shared by both loops, the loops beingclosed except for said transfer through said device; and removing the atleast one waste component from the regeneration loop.
 41. The method ofclaim 40, wherein the first and second fluids include dialysate.
 42. Themethod of claim 40, wherein the first fluid includes blood and thesecond fluid includes dialysate.
 43. The method of claim 40, whereinremoving the waste component includes flowing the second fluid in theregeneration loop through a waste sorbent and absorbing at least some ofthe waste component.
 44. The method of claim 40, which includes the stepof heating the at least one of the first and second fluids.
 45. Themethod of claim 40, which includes the step of removing ultrafiltratefrom at least one of the first and second fluids.
 46. The method ofclaim 40, which includes the step of adding dialysate to at least one ofthe first and second fluids.
 47. The method of claim 40, which includesthe step of adding concentrate to at least one of the first and secondfluids.
 48. The method of claim 40, which includes the step of removinggas from at least one of the first and second fluids.
 49. The method ofclaim 40, which includes the step of balancing the flow of fluid in atleast one of the patient loop and the regeneration loop.
 50. The methodof claim 40, which includes the step of sensing a volume of flow offluid in at least one of the patient loop and the regeneration loop. 51.A method of moving fluid in a peritoneal dialysis system comprising thesteps of: continuously recirculating dialysate through a container in apatient loop; continuously recirculating dialysate through the containerin a regeneration loop; and continuously moving at least one wastecomponent from the patient loop to the regeneration loop through thecontainer shared by both loops, the loops being closed except for thetransfer through the container.
 52. The method of claim 51, whichincludes the step of recirculating dialysate through the regenerationloop at a different rate than a rate at which dialysate is recirculatedthrough the patient loop.
 53. A method of performing continuous flowperitoneal dialysis comprising the steps of: continuously recirculatingdialysate fluid through a closed patient loop; continuouslyrecirculating regeneration fluid through a closed regeneration loop;passing the dialysate fluid and the regeneration fluid past oppositesides of a dialyzer membrane; and regenerating the regeneration fluidafter the regeneration fluid exits the dialyzer.
 54. The method of claim53, wherein recirculating dialysate fluid through the closed patientloop includes passing the fluid through a portion of a patient.
 55. Themethod of claim 53, wherein recirculating dialysate fluid through theclosed patient loop includes passing the fluid through a sleepingpatient.
 56. The method of claim 53, wherein recirculating dialysatefluid through the closed patient loop includes passing the fluid througha patient at nighttime.
 57. A method of performing continuous flowdialysis comprising the steps of: performing continuous flow peritonealdialysis with a closed loop dialysis device at a first point in time;and performing continuous flow hemodialysis via the same closed loopdialysis device at a second point in time.
 58. The method of claim 57,wherein the continuous flow peritoneal dialysis and the continuous flowhemodialysis are performed on the same patient.
 59. The method of claim57, which includes an intermediate step of removing a disposablecassette used with the device and coupling a new disposable cassette tothe device.
 60. The method of claim 57, which includes an intermediatestep of removing a dual lumen peritoneal dialysis catheter and replacingsaid catheter with a hemodialysis needle.
 61. The method of claim 57,which includes an intermediate step of removing a hemodialysis needleand replacing said needle with a dual lumen peritoneal dialysiscatheter.